feat(PromisePipe): add pipe for promises

modules/angular2/test/change_detection/pipes/promise_pipe_spec.js

@@ -0,0 +1,96 @@
+import {ddescribe, describe, it, iit, xit, expect, beforeEach, afterEach,
+  AsyncTestCompleter, inject, proxy, SpyObject} from 'angular2/test_lib';
+import {IMPLEMENTS} from 'angular2/src/facade/lang';
+import {PromisePipe} from 'angular2/src/change_detection/pipes/promise_pipe';
+import {WrappedValue} from 'angular2/src/change_detection/pipes/pipe';
+import {ChangeDetectorRef} from 'angular2/src/change_detection/change_detector_ref';
+import {PromiseWrapper} from 'angular2/src/facade/async';
+
+export function main() {
+  describe("PromisePipe", () => {
+    var message = new Object();
+    var pipe;
+    var completer;
+    var ref;
+
+    beforeEach(() => {
+      completer = PromiseWrapper.completer();
+      ref = new SpyChangeDetectorRef();
+      pipe = new PromisePipe(ref);
+    });
+
+    describe("supports", () => {
+      it("should support promises", () => {
+        expect(pipe.supports(completer.promise)).toBe(true);
+      });
+
+      it("should not support other objects", () => {
+        expect(pipe.supports("string")).toBe(false);
+        expect(pipe.supports(null)).toBe(false);
+      });
+    });
+
+    describe("transform", () => {
+      it("should return null when subscribing to a promise", () => {
+        expect(pipe.transform(completer.promise)).toBe(null);
+      });
+
+      it("should return the latest available value", inject([AsyncTestCompleter], (async) => {
+        pipe.transform(completer.promise);
+
+        completer.resolve(message);
+
+        PromiseWrapper.setTimeout(() => {
+          expect(pipe.transform(completer.promise)).toEqual(new WrappedValue(message));
+          async.done();
+        }, 0)
+      }));
+
+      it("should return unwrapped value when nothing has changed since the last call",
+          inject([AsyncTestCompleter], (async) => {
+        pipe.transform(completer.promise);
+        completer.resolve(message);
+
+        PromiseWrapper.setTimeout(() => {
+          pipe.transform(completer.promise);
+          expect(pipe.transform(completer.promise)).toBe(message);
+          async.done();
+        }, 0)
+      }));
+
+      it("should dispose of the existing subscription when subscribing to a new promise",
+          inject([AsyncTestCompleter], (async) => {
+        pipe.transform(completer.promise);
+
+        var newCompleter = PromiseWrapper.completer();
+        expect(pipe.transform(newCompleter.promise)).toBe(null);
+
+        // this should not affect the pipe, so it should return WrappedValue
+        completer.resolve(message);
+
+        PromiseWrapper.setTimeout(() => {
+          expect(pipe.transform(newCompleter.promise)).toBe(null);
+          async.done();
+        }, 0)
+      }));
+
+      it("should request a change detection check upon receiving a new value",
+          inject([AsyncTestCompleter], (async) => {
+        pipe.transform(completer.promise);
+        completer.resolve(message);
+
+        PromiseWrapper.setTimeout(() => {
+          expect(ref.spy('requestCheck')).toHaveBeenCalled();
+          async.done();
+        }, 0)
+      }));
+    });
+  });
+}
+
+@proxy
+@IMPLEMENTS(ChangeDetectorRef)
+class SpyChangeDetectorRef extends SpyObject {
+  constructor(){super(ChangeDetectorRef);}
+  noSuchMethod(m){return super.noSuchMethod(m)}
+}